1. Field of the Invention
The present invention relates to a webbing retractor for taking up a webbing of a seat occupant of a vehicle.
2. Description of the Related Art
Among webbing retractors, there is a type in which when the rotation of a webbing take-up shaft for drawing out a webbing is stopped upon detection of a predetermined acceleration. The take-up shaft receives the webbing-drawing-out force and moves. At that time a spool fixed to the take-up shaft actuates a clamping means. The clamping means clamps an intermediate portion of the webbing so as to prevent the drawing-out of the webbing (Japanese Patent Laid-Open No. 205532/1986).
Since with this retractor an intermediate portion of the webbing is clamped and locked, the webbing taken up by the webbing take-up shaft does not become tightly wound, and the amount of pay out of the webbing after being locked is limited.
However, with this retractor, since the clamping means is actuated as the take-up shaft moves, an inner end of a spiral spring, which is an output portion of the take-up means, moves together with the take-up shaft. Accordingly, if an arrangement is adopted in which a tension reducer for reducing the tension of the webbing after the seat occupant secures the webbing and other related devices are provided on the take-up shaft, it is necessary for these devices to also move together with the take-up shaft. Hence, designing becomes extremely difficult.